High OG - orange/coriander Witbier

After I cooled the wort and added water up to 5 gallons my OG came to 1.105. (Was supposed to be around 1.051 for this Witbier) So once I noticed the original boil was supposed to be 2.5 gal rather than 3, I added more water to dilute what was going in the fermenter. I got it down to 1.074 OG and the volume came to approximately 6.1gal.

Will standard yeast pack suffice?
Should I let it set longer in the fermenter to account for the extra volume?
Any recommendations would greatly be appreciated! I really don't know what to expect and I don't want to lose this beer!

Please list your recipe...that is a huge discrepancy

EDIT: I have a feeling your sample contained mostly undiluted wort and that your OG is right where it should be. Don't make any more adjustments.

Just transferred into secondary and re-measured SG, came out to 1.014. Tasted great. You could be right about the measurement, but I diluted and measured 3 times before going into fermenter and it came down from 1.100 to 1.074... I'll know when I get my first taste after bottle conditioning. Side note: I added 6Tbsp. natural orange juice into secondary, then racked.